This invention relates to a coating for textile substrates such as carpet and upholstery and its method of use.
Various tuft-lock coatings, carpet-backing adhesives and non-woven binder compositions for textile substrates are known. For example, U.S. Pat. Nos. 3,505,156 to Handscomb et al.; 3,695,987 to Wistozsky, 4,595,617 to Bodgany and 4,808,459 to Smith et al. propose the use of various latexes for use as tuft-lock coatings. Exemplary carpet-backing adhesives are proposed in, for example, U.S. Pat. Nos. Re 31,826 to Machell, 3,390,035 to Sands, 4,876,293 to Durney et al., 5,093,449 to Durney-Cronin et al., and 4,368,282 to Bogdany. Exemplary non-woven binder compositions are disclosed, for example, in U.S. Pat. Nos. 4,251,581 to Schoppa et al., and 4,673,616 to Goodwin.
These compositions are often based on styrene-butadiene copolymers which have in recent years attracted a lot of adverse publicity in carpet backing applications due to the presence of a by-product produced during the manufacture of styrene-butadiene latices known as 4-phenyl cyclohexene ("4-PCH"). This chemical formed only when styrene and butadiene are reacted is alleged to be responsible for the odor associated with new carpet. There is also the negative public perception that "sick building syndrome" is primarily caused by the off gassing of this chemical from carpets. Environmental concerns are also forcing carpet manufacturers to look at ways to recycle or reprocess used carpet to minimize land filling. Carpets made with styrene-butadiene adhesives are less suitable towards reprocessing using conventional extrusion and compression molding techniques. Styrene-butadiene adhesives also tend to phase separate during the extrusion process and thus lead to products with inferior mechanical properties. In addition, styrene-butadiene adhesives also typically do not depolymerize under extrusion conditions and this potentially makes it less amenable to recycling. Given this public scenario, it is considered desirable to eliminate or reduce the use of styrene and related aromatic compounds in polymeric coatings used with textile substrates, and particularly butadiene-based formulations, while avoiding any significant reduction in physical and mechanical properties of the polymeric coating.
Therefore, it is an object of the present invention to provide a polymer coating which eliminates the use of styrene in a butadiene-based formulation without sacrificing desirable physical or mechanical properties.